The Probiotic Pediococcus acidilactici in the Feed of Salmonids: A Strategy to Improve Reproductive Parameters

This study investigated the effects of dietary supplementation with the probiotic Pediococcus acidilactici on the reproductive performance and offspring viability of male Atlantic salmon (Salmo salar). A total of 48 mature males were divided into three groups-Group A (control, no probiotic), Group B (60-day supplementation), and Group C (120-day supplementation). The fish were kept in 10 m³ tanks at a constant temperature of 9 °C under a natural photoperiod and evaluated for multiple reproductive and physiological parameters. The results demonstrate that Group C exhibited significantly higher gonad weight, gonadosomatic index (GSI), and sperm concentration than Groups A and B. The blood biochemistry revealed reduced bilirubin and alanine aminotransferase (ALT) levels in Group C; however, values were within normal reference ranges for the species in all groups. While sperm quality parameters such as membrane integrity and motility showed no significant differences, fertility and embryo viability were significantly higher in Group C across all three developmental stages (180, 300, and 380 accumulated thermal units, ATUs). Additionally, Group C showed lower rates of embryonic malformation and mortality at later stages of development. Statistical analyses confirmed a significant interaction between treatment duration and embryo viability, with the 120-day probiotic treatment (Group C) producing the best outcomes. These findings support the hypothesis that P. acidilactici supplementation positively influences male reproductive parameters and improves embryo quality and survival in Atlantic salmon.